1. Field of the Invention
This invention relates to electrophotocopy machines and, in particular, to a control system for a reciprocating carriage that is mounted on such a machine.
Electrophotocopy machines are well known devices that are used for reproducing all forms of documents. These machines are usually either of the plain paper type or the coated paper type. The plain paper machines have a reuseable photoconductor and produce a copy on bond paper. The coated paper machines use a special paper that has been treated with a photosensitive substance so that the copy sheet functions as the photoconductor. These machines include a number of processing stations. At one station, the photoconductor is uniformly electrostatically charged. At another, the document to be copied is illuminated. At an imaging station the charged photoconductor is exposed to an image of the illuminated document to selectively discharge light struck areas of the photoconductor thereby forming a latent electrostatic image thereon. At a developing station, the latent image is developed by applying either a wet or dry type developer. In plain paper copiers, the developed image is thereafter transferred to a plain paper copy sheet. Finally, the toner is fixed to the copy sheet in one of a number of well known ways in order to yield a finished copy.
It is readily apparent from the foregoing description that the exposing and imaging stations perform an important function in copying machines because they provide the nexus between the document and the photoconductor. There are a number of configurations and combinations of such station. One kind of machine includes a sheet handling and feeding apparatus for moving an original document across a fixed, transparent illumination slit. Such machines, however, cannot handle bulky documents such as books. Another kind of machine uses a stationary, flat glass platen on which a book or single folio document is illuminated by a flash lamp. A lens focuses the flashed image onto a substantially flat photoconductor. Other stationary platen machines scan expose the photoconductor to the document by means of a movable mirror, lens and lamp arrangement. Still other machines use a fixed lens, mirror and lamp arrangement combined with a movable (reciprocating) carriage that carries a document face down on a transparent platen across an illuminating station. The carriage, the illuminating station, and other processing stations are operated by a control system that moves the carriage in a known, timed relationship with the photoconductor that move (in synchronism) past the respective exposure station and the imaging station. Hence, the control system is an important element of the reciprocating carriage copy machine.
2. Description of the Prior Art
The prior art includes a number of controls for reciprocating carriage copy machines. For example, in U.S. Pat. No. 3,471,230 there is shown a multicomponent electrical network for controlling such a machine. Included in that network are at least two switches and relays for separately controlling the forward and return strokes of the carriage. Other examples of dual switch and relay controls are shown in U.S. Pat. Nos. 3,424,526 and 3,704,944. Such multiple switch-relay controls are expensive, add to the overall complexity of manufacture, and present additional areas where elements can malfunction.
Therefore, it is an object of this invention to provide a simple control system for a reciprocating carriage of an electrophotocopy machine.
It is also an object to provide a control system having a common actuating means for actuating the illuminating station, controlling the direction of travel of the carriage and the operation of a severing means for cutting copy sheets from a web of copy paper.
An additional object is to provide an electrophotocopy machine which is simple in design, inexpensive to manufacture, efficient and reliable in operation.